Creating data in Prefuse
I am new to Prefuse. The demo examples are all loaded data from a file/database. Is there any way to create the data dynamically instead of loading from file. For example, I want to create a 开发者_JAVA百科tree data structure and visualize this. Any simple working example would be really helpful for me.
I've just been attacking this problem. Here's a tweaked version of Example.java
which shows one way to make it happen.
Instead of loading data from socialnet.xml
, I'm generating it programatically (based on Aggregate.java
but without the aggregation stuff) and adding one field to each Node
and each Edge
. The Node
field is a simple boolean flag which controls the colour it's rendered; the Edge
field is a label - but it's not being rendered yet. I'm still working on that one! :-)
The question-specific code is in makeGraph()
. The basic approach is to create a Table
(well, one each for nodes and edges), and add columns to those tables defining the shape of the data; then when you add your nodes and edges, you can add the corresponding data. One gotcha is that for edges you must include columns for the edge's source/target nodes - see the Graph
and Table
documentation for more details. There are other ways to do this (e.g. involving Schema
) but I haven't sussed them out yet.
Hope this helps.
import javax.swing.JFrame;
import prefuse.Constants;
import prefuse.Display;
import prefuse.Visualization;
import prefuse.action.ActionList;
import prefuse.action.RepaintAction;
import prefuse.action.assignment.ColorAction;
import prefuse.action.assignment.DataColorAction;
import prefuse.action.layout.graph.ForceDirectedLayout;
import prefuse.activity.Activity;
import prefuse.controls.DragControl;
import prefuse.controls.PanControl;
import prefuse.controls.ZoomControl;
import prefuse.data.Edge;
import prefuse.data.Graph;
import prefuse.data.Node;
import prefuse.data.Table;
import prefuse.render.DefaultRendererFactory;
import prefuse.render.EdgeRenderer;
import prefuse.render.Renderer;
import prefuse.render.ShapeRenderer;
import prefuse.util.ColorLib;
import prefuse.visual.VisualItem;
public class Example extends Display {
private Graph makeGraph() {
// Create tables for node and edge data, and configure their columns.
Table nodeData = new Table();
Table edgeData = new Table(0,1);
nodeData.addColumn("flag", boolean.class);
edgeData.addColumn(Graph.DEFAULT_SOURCE_KEY, int.class);
edgeData.addColumn(Graph.DEFAULT_TARGET_KEY, int.class);
edgeData.addColumn("label", String.class);
// Need more data in your nodes or edges? Just add more
// columns.
// Create Graph backed by those tables. Note that I'm
// creating a directed graph here also.
Graph g = new Graph(nodeData, edgeData, true);
// Create some nodes and edges, each carrying some data.
// There are surely prettier ways to do this, but for the
// example it gets the job done.
for ( int i=0; i<3; ++i ) {
Node n1 = g.addNode();
Node n2 = g.addNode();
Node n3 = g.addNode();
n1.setBoolean("flag", false);
n2.setBoolean("flag", true);
n3.setBoolean("flag", true);
Edge e1 = g.addEdge(n1, n2);
Edge e2 = g.addEdge(n1, n3);
Edge e3 = g.addEdge(n2, n3);
e1.setString("label", "a");
e2.setString("label", "a");
e3.setString("label", "a");
}
Edge e4 = g.getEdge(g.addEdge(0, 3));
Edge e5 = g.getEdge(g.addEdge(3, 6));
Edge e6 = g.getEdge(g.addEdge(6, 0));
e4.setString("label", "b");
e5.setString("label", "b");
e6.setString("label", "b");
return g;
}
public Example() {
super(new Visualization());
Graph graph = makeGraph();
m_vis.addGraph("graph", graph);
m_vis.setInteractive("graph.edges", null, false);
m_vis.setValue("graph.nodes", null, VisualItem.SHAPE,
new Integer(Constants.SHAPE_ELLIPSE));
Renderer nodeR = new ShapeRenderer(20);
EdgeRenderer edgeR = new EdgeRenderer(prefuse.Constants.EDGE_TYPE_CURVE, prefuse.Constants.EDGE_ARROW_FORWARD);
DefaultRendererFactory drf = new DefaultRendererFactory();
drf.setDefaultRenderer(nodeR);
drf.setDefaultEdgeRenderer(edgeR);
m_vis.setRendererFactory(drf);
int[] palette = new int[] {
ColorLib.rgb(255,180,180), ColorLib.rgb(190,190,255)
};
ColorAction nStroke = new ColorAction("graph.nodes", VisualItem.STROKECOLOR);
nStroke.setDefaultColor(ColorLib.gray(100));
DataColorAction nFill = new DataColorAction("graph.nodes", "flag",
Constants.NOMINAL, VisualItem.FILLCOLOR, palette);
ColorAction edges = new ColorAction("graph.edges",
VisualItem.STROKECOLOR, ColorLib.gray(200));
ColorAction arrow = new ColorAction("graph.edges",
VisualItem.FILLCOLOR, ColorLib.gray(200));
ActionList color = new ActionList();
color.add(nStroke);
color.add(nFill);
color.add(edges);
color.add(arrow);
ActionList layout = new ActionList(Activity.INFINITY);
layout.add(new ForceDirectedLayout("graph"));
layout.add(new RepaintAction());
m_vis.putAction("color", color);
m_vis.putAction("layout", layout);
setSize(720, 500); // set display size
pan(360, 250);
setHighQuality(true);
addControlListener(new DragControl());
addControlListener(new PanControl());
addControlListener(new ZoomControl());
m_vis.run("color");
m_vis.run("layout");
}
public static void main(String[] argv) {
Example ex = new Example();
JFrame frame = new JFrame("prefuse example");
frame.getContentPane().add(ex);
frame.pack(); // layout components in window
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true); // show the window
}
}
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